Bringing War Back In provides a fresh theory connecting war and state formation that incorporates the contingency of warfare and the effects of war outcomes in the long run. The book demonstrates that international wars in nineteenth-century Latin America triggered state-building, that the outcomes of those wars affected the legitimacy and continuity of such efforts, and that the relative capacity of states in this region today continues to reflect those distant processes. Combining comparative historical analysis with cutting edge social science methods, the book provides a comprehensive picture of state formation in nineteenth-century Latin America that is compelling for readers across disciplines, breathes new life into bellicist approaches to state formation, and offers a novel framework to explain variation in state capacity across Latin America and the world.